This invention relates to an ice machine and a method for controlling the ice machine. In particular, the method and ice machine include novel and improved ice cube detection, error code processing, controller installation, and servicing.
Electronic controllers for ice machines are known. For example, U.S. Pat. No. 5,477,694 describes an ice machine having an electronic controller that responds to trouble events that occur during the running of the ice machine according to a diagnostic procedure. Also, U.S. Pat. No. 5,582,018 describes an ice machine and a controller that controls the ice machine to prevent slush from forming during a freeze cycle in which the ice machine forms ice on an evaporator thereof. Each of these patents discloses ice cube detection devices that are workable. However, their performance is subject to variations due to manufacturing tolerance and/or to environmental influence, e.g., mineral buildup, water drops, mist and the like.
The detection of objects by an optical device is also known. The aforementioned patents employ light sources and light detectors. Also, U.S. Pat. No. 6,265,709 discloses an optical detector and filtering procedure that uses variable sweep bands or random variations in the optical signal period to filter undesired noise. However, the optical detector performance is subject to variations in manufacturing tolerances.
There is a need for a method and an ice machine with a reliable ice cube detection procedure that is impervious to manufacturing variations and that is capable of counting ice cubes as well as detecting a bin full condition.
There is also a need for a method and an ice machine that is capable of tracking trouble event performance either remotely or in the field and of uploading and/or downloading data or program code from or to the controller of the ice machine
There is also a need for a method and a universal controller that can be used in a plurality of different ice machines.
The method of the present invention controls an ice machine by developing error codes as the ice machine runs. The error codes are recorded in a log in a memory. A time of occurrence is assigned to at least one of the error codes wherein the time of occurrence is measured from the time of an installation event of the ice machine. The error codes and/or times of occurrence are retrievable.
According to one aspect of the method of the present invention, the ice machine includes a communication port and the error codes are retrievable via the communication port. According to another aspect of the present invention, at least one of the error codes is displayed. According to a feature of this aspect, the ice machine includes a plurality of display lights. The error codes are displayed as unique combinations of energized ones of the display lights. According to this aspect, the at least one error code in some embodiments is a most recent error code.
According to a further feature of the method of the present invention, the ice machine also includes a plurality of switches. The method detects the operation of one or more of the plurality of switches in a predetermined sequence. The most recent error code is then displayed. The method further detects the operation of a toggle switch and displays a second error code by energizing a second unique combination of the plurality of display lights. The two error codes are alternately displayed in response to further toggling of the toggle switch.
According to another embodiment of the method of the present invention, a controller is installable in any one of a plurality of different models of an ice machine. The method sets the controller to one of a plurality of program styles that corresponds to a selected one of the plurality of models. The selected program style is displayed to an operator for visual verification that the selected program style corresponds to the selected model of the ice machine. According to one aspect of this embodiment, the ice machine includes a plurality of display lights and the program style is displayed by energizing a combination of the plurality of lights that correspond to the program style.
According to yet another embodiment of the method of the present invention, the ice machine has an optical detector that detects ice cubes when in a field of vision thereof. The method illuminates the optical detector with a periodic optical signal. A plurality of samples of an output signal of the optical detector is provided. A difference between at least first and second ones of the samples is compared with a threshold to detect the ice cubes when falling through the field of vision. According to one aspect of this embodiment of the method, the difference is between signal samples that correspond to consecutive peaks of the periodic optical signal.
According to another aspect of this embodiment of the method, a determination is made that one of the ice cubes is passing through the field of vision if the difference penetrates the threshold a predetermined number of times during an interval of the periodic optical signal, the interval containing a plurality of cycles the optical signal.
According to another aspect of this embodiment of the method of the present invention, it is determined that a bin of the ice machine is full of ice cubes if the difference penetrates the threshold. In this embodiment, the difference is between signal samples that correspond to an adjacent peak and valley of the periodic optical signal.
Various embodiments of the ice machine of the present invention include a controller that performs operations that correspond to the method embodiments and aspects thereof.